Why does my knee hurt?

From stiffness and instability, to popping or crunching noises, knee pain is a common issue that can affect all people differently, regardless of age. The causes of knee pain can range from injury like a torn ligament, to a medical issue like arthritis.

“Not all knee pain is serious or requires medical attention,” explains Dr. Joel Smith, an orthopedic surgeon affiliated with Sharp HealthCare. “See your doctor when you find yourself unable to put weight on your knee; notice pain or swelling that limits normal activity; or have a fever in addition to knee pain and swelling.”

The most common knee injuries associated with knee pain are ligament injuries, cartilage tears and arthritis of the knee.

Ligament injuries — There are four main ligaments of the knee that help it function properly. A ligament tear directly affects the ability to participate in normal activities like walking and exercising. Not all knee ligaments injuries are the same, or require the same treatment.

Cartilage tears — Cartilage is a type of tissue that is strong like a bone, but flexible like a ligament, and is found on either side of the knee joint. Torn cartilage is a common injury — associated with the “popping” noise. Surgery is often required for this kind of tear.

Arthritis — There are many different kinds of arthritis that can be associated with stiffness and swelling of the knee.

While some causes of knee pain — like certain types of arthritis — are genetic, there are risk factors that can increase a person’s overall risk of knee problems. These include being overweight, a lack of strength, playing certain sports such as basketball and soccer, or a previous injury.

“Not all types of knee pain are preventable, but there are ways to reduce the discomfort and disability of living with this issue,” says Dr. Smith. “To prevent knee pain or developing certain knee injuries, I always tell my patients to maintain a healthy weight, exercise regularly at a level that is comfortable for them, and stay flexible through balance and stability training.”